Epidemiological and histopathological profile of malignant melanoma in Malawi

Abstract

Background: Studies on malignant melanoma have largely focused on Caucasian populations due to higher incidence in lighter-skinned individuals. While there is a well developed body of literature describing melanoma in African-Americans, much less is known about melanoma in black Africans. Prior reports have suggested that it is reportedly extremely rare in black Africans who are considered to mostly have the acral lentiginous subtype. However, an accurate understanding of melanoma in this part of the world is hindered by the very limited nature of prior publications. The aim of this study was to determine the epidemiological profile, anatomical distribution and histopathological features of melanoma presenting in Africans at a tertiary referral hospital in Malawi. Methods: This is a retrospective study that characterized melanoma cases diagnosed from January 2012 to December 2017, at a cancer referral centre in Malawi. All confirmed, malignant melanoma cases during the study period were retrieved. Data abstracted included age, sex, anatomic site and whether it was a primary or metastatic site. Breslow thickness in millimetres, Clark level of invasion, presence of ulceration and melanoma subtype were also evaluated. Results: One hundred thirty-two cases were included in the study, 81 (61%) were female and 26 (20%) were from a metastatic site. The mean age was 57 years (sd = 15) with the majority in the age group 60-69 years. Males presented at an older age than females. Ninety five percent of cutaneous melanomas were located on acral sites, most commonly the foot (87%) and the most common histopathological subtype was acral lentiginous. Eighty four percent presented with a Breslow thickness over 4 mm (median 9 mm). Conclusion: Our study shows that malignant melanoma occurs in black people in Malawi and may be an under-appreciated malignancy. While long term clinical follow-up was not available, most patients presented at late stages of the disease, supporting a poor prognosis. These results suggest that increased awareness of melanoma in black Africans and earlier intervention may have meaningful impacts on outcomes and survival.